It is known to connect the ends of sheet metal ducts by providing the ducts at opposite ends of the panels of the ducts which open toward one another and wherein there is disposed at the corners of the ducts angle plates which have opposite ends thereof seated in and connect together adjacent angle flanges. The ducts are then secured together by way of fasteners which connect together the angle plates.
Systems for connecting the flanges are described in U.S. Pat. No. 4,466,641 assigned to the Lockformer Company and U.S. Pat. No. 4,579,375 assigned to Engel Industries, Inc. The system described in the Lockformer '641 patent is commonly referred to as the transverse duct connecter (TDC) system and the system described in the Engel '375 patent is commonly referred to as the transverse duct flange (TDF) system.
Prior to the issuance of related patent numbers 5,283,944 and 5,321,880 above noted, the angle plates, also referred to as corners, were manually secured to the ducts by manually forcing the angle plates into the duct channel flanges. This was a time consuming and thus costly operation since each angle plate was positioned individually. The aforesaid '944 and '880 patents describe an apparatus and method for automatically assembling an angle plate in channel shaped flanges at ends of duct panels joined in a corner to form a duct section. The apparatus includes a platen for engaging an end of a duct section, positioning means for locking a duct in a pre-selected position relative to the platen, angle plate advancing means for advancing an angle plate into engagement with a corner of a clamped duct section in axial alignment with the duct flanges, and means for pressing an angle plate into the corners. The apparatus described in the aforesaid '944 and '880 patents can be a single head machine where corners are inserted at one end of the duct section only or a dual headed machine where corners are simultaneously inserted at both ends of a duct section. The single head and dual headed machines are commercially available from Iowa Precision Industries, Cedar Rapids, Iowa, under the trademark CORNERMATIC corner inserter. These apparatus, used in a shop environment with the joined sections then transported to a job site where the duct sections are assembled for use in a heating and air conditioning system, satisfy a long felt need in the industry and have been enthusiastically received by the industry.
Subsequent to the aforesaid '944 and '880 patents, U.S. Pat. No. 5,495,652 issued also describing an apparatus for automatically inserting corners.
The present invention describes modifications to the apparatus and method described in the '944 and '880 patents wherein the apparatus is mobile permitting the use of the apparatus in field applications. Additionally, the apparatus is versatile and can be used with various shaped duct sections.